This invention relates to the manufacture of plastic cups, and more particularly to drinking cups made from both plastic, foam sheet and plastic, foam beads.
Foam plastic drinking cups have gained a substantial portion of the market which formerly used only cups made of paper. A large number of these plastic drinking cups are manufactured by a bead molding process. However, this process presents two obstacles: due to expansion of the beads, the cup cannot be made thin enough for many applications, and, the cup cannot be printed prior to its assembly. These problems gave rise to a second method of manufacturing plastic foam cups, wherein two pieces of foam sheet are molded to form the cup. The foam sheet method requires that the cup bottom be blanked and shaped prior to molding. Shaping the bottom into a cup-like section before placing it in the mold has proved to be very difficult. The instant invention, therefore, eliminates the bottom forming steps while retaining the advantages of a foam sheet sidewall.